Synopsis On 27 January 1999, the CANMAR SPIRIT was upbound in the Port of Montreal, Quebec, making way towards section 78 for berthing and ensuing cargo operations. As a normal part of the duties during manoeuvring, a member of the engine-room crew was detailed to start two of the ship's main air compressors. After having started the No. 1 compressor without incident, he proceeded to initiate the start-up of the No. 3 compressor. During the start-up sequence, a sudden and violent over-pressurization occurred within the compressor. Damage to the compressor included burst cooler tubes in the second-stage (after) cooler, burst compressor casing in way of the cooling water chamber, and a flayed flexible delivery air line. The second-stage air cooler cover also burst and fragments of this piece were projected outward in a shrapnel-like fashion, seriously injuring the crew member. As the CANMAR SPIRIT had not yet berthed, a harbour tug was used to evacuate the injured crew member under the supervision and assistance of trained ambulance technicians. The crew member was later pronounced dead at the hospital. The Board determined that the No. 3 compressor on the CANMAR SPIRIT experienced a severe and near instantaneous over-pressurization due to the system delivery valve remaining closed while the compressor was started. This omission, combined with the malfunctioning air relief valves, created a closed circuit in which certain components of the compressor could not withstand the ever-increasing pressure. A factor contributing to the accident was the less-than-adequate maintenance of non-return valves. Ce rapport est galement disponible en franais. 1.0 Factual Information 1.1 Particulars of the Vessel 1.1.1 Description of the Vessel The CANMAR SPIRIT is a 793 twenty-foot equivalent units (TEU)[2] container ship with four holds. The accommodation and machinery space are located aft. She is a regular caller at the Port of Montreal being on the North Atlantic trade route between Europe and North America, with an average service speed of 16.5 knots. Launched in 1971 as the CP TRADER, the vessel has seen a number of management and name changes. In 1982 she was renamed ANDES TRADER, in 1986, SAN LORENZO and in 1994, CANMAR SPIRIT. 1.2 History of the Voyage On the afternoon of 18 January 1999, the CANMAR SPIRIT left Lisbon, Portugal, bound for Montreal. By the early afternoon of 27 January 1999, after an uneventful ocean passage, the vessel was approaching section 78 in the Port of Montreal to berth and commence cargo operations. In the engine-room, the crew had been mustered to manoeuvring stations and were going about their various tasks. The chief engineer was present in the control room with the officer of the watch (OOW). At approximately 1345 eastern standard time,[3] the duty greaser was detailed to start up main air compressors Nos. 1 and 3. After starting the No. 1 compressor without incident, he proceeded to start the No. 3 compressor. Shortly after the initiation of the start-up procedure, at approximately 1400, a sudden and violent over-pressurization occurred within the compressor. An explosion-like noise was heard throughout the vessel and a white vapour was observed in the vicinity of the compressor by the crew members in the control room. The OOW went immediately to the scene of the accident and saw the duty greaser walking uneasily and then collapsing close to the No. 1 compressor, approximately eight metres from the scene of the accident. It would appear that the victim was in the process of closing the first- and second-stage purge drain valves when the over-pressurization occurred. The act of closing the purge drain valves positioned him near and just slightly to the right of the second-stage air cooler cover. The complete and violent failure of this piece of equipment during the over-pressurization of the compressor caused serious injuries to the duty greaser that later proved to be fatal. First aid was administered to the injured crew member where he lay by the ship's personnel. Montreal Marine Communications and Traffic Services was advised of the situation and the tug OCEAN INTREPID, with ambulance technicians on board, was called to the scene immediately. By 1418, the ambulance technicians had boarded the CANMAR SPIRIT by way of the tug and were administering first aid to the victim. At approximately 1455, the injured crew member was evacuated via the tug ashore, and then to a local hospital under the supervision and assistance of the ambulance technicians. Once the injured crew member had been evacuated, the berthing operation of the CANMAR SPIRIT was successfully completed. Upon arrival at the hospital, the injured crew member was pronounced dead by the hospital authorities. 1.3 Injuries to Persons It has been established that the duty greaser died as a result of injuries sustained from fragments of metal projected at high velocity. It is most probable that the fragments of metal originated from the second-stage outlet cover that burst during the over-pressurization of the compressor. 1.3.1 Crew Trauma In the 48 hours after the accident, a plethora of officials including inspectors, investigators, Class surveyors, police, owner's and insurance representatives visited the vessel. All had many questions in order to satisfy their mandates, and the senior officers--particularly the master and chief engineer--were heavily solicited. Given the seriousness of the situation, this was to be expected, but reportedly increased the stress and anguish already being suffered by the crew. 1.4 Damage to the Vessel The No. 3 compressor, which is of the non-oil-free, reciprocating, water-cooled type, was damaged beyond cost-efficient repair. The second-stage air cooler cover was burst and fragments of this piece were projected outward at high velocity in a shrapnel-like fashion. Other damage to the compressor included burst cooler tubes in the second-stage (after) cooler, burst compressor casing in way of the cooling water chamber and a flayed flexible delivery air line. Of the 33 second-stage cooler tubes, 18 were found to be ruptured. 1.5 Certification 1.5.1 Vessel The last annual survey of the CANMAR SPIRIT was at Rijeka, Yugoslavia, on 09 September 1998. The Cargo Ship Safety Construction Certificate was issued at London on 16 August 1996 and was due to expire on 14 May 2001. The Cargo Ship Safety Equipment Certificate was issued at Hong Kong on 11 June 1997 and was last endorsed at Montreal on 12 June 1998. 1.5.2 Personnel The victim held a certificate of competency to perform the duties of a ship's greaser issued on 01 October 1996 with the endorsement issued in December 1997. He also held a firefighting certificate, a certificate of ability for handling lifesaving appliances, and a certificate of search, rescue and survival at sea as per the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers, 1978. The chief engineer held a first class engineering certificate issued in 1989. The most recent continued proficiency endorsement was acquired in 1997. The master held a master mariner certificate issued in 1972. The most recent continued proficiency endorsement was acquired in 1997. All of the above certificates were issued by the Ministry of Maritime Affairs, Croatia. 1.6 Personnel History The duty greaser killed by the burst compressor had joined the CANMAR SPIRIT on 09 December 1998, seven weeks before the accident. He had been assigned the 1200 to 1600 watch and was considered a dependable employee and conversant about engine-room procedures. He had previous experience operating the compressors and was knowledgeable about the start-up procedures. It was his first tour of duty on board the CANMAR SPIRIT. The master had been at sea since 1965, and had acted as master on various ships since 1978. He had joined the CANMAR SPIRIT on 13 January 1999 for the first time. The chief engineer had been employed in a seafaring capacity since 1977, and as chief on various vessels since 1996. He had joined the vessel on 09 December 1998 for the first time. 1.7 Laboratory Examination and Testing 1.7.1 Non-Return Valves and Relief Valves All three compressors on board the CANMAR SPIRIT are equipped with non-return (check) valves. The function of the non-return valve is to prevent the reverse flow of air from the air receiver back to the compressor. Upon examination, it was found that the non-return valve on each of the three compressors was not functioning correctly, thus allowing high-pressure air to leak back into the compressor. The compressors are also equipped with low- and high-pressure relief valves on the first and second stages respectively. They are of the plunger and spring variety and are adjusted to open at 10 per cent above their associated stage operating pressure. Upon examination and testing of the failed compressor's relief valves, it was found that the second-stage relief valve was completely blocked on the inlet side by burnt oil residues, and at least 50 per cent blocked on the outlet side by similar residues. In this condition, it is highly unlikely that the valve would have functioned properly. The first-stage relief valve was damaged during the compressor failure by flying debris and was not tested, but a visual examination showed it to be completely blocked by oily, sooty residues. The relief valves from the other two compressors were also examined and tested. Only one first-stage and one second-stage valve worked as specified, giving an overall failure rate of slightly more that 66 per cent (four out of six relief valves failed to work properly). The malfunctions are attributable to an oily, sooty build-up. 1.7.2 Jabsco Water Pump The Jabsco cooling water pump from the failed compressor, which supplies water to the first- and second-stage air cooler cylinder jackets and cylinder heads, was disassembled and examined. Four of the nine impeller vanes had fractured off, two of which were found jammed between the impeller and the pump housing. A fifth vane was very close to complete fracture. The vane fracture surfaces were examined under magnification and revealed an appearance consistent with a failure having occurred through a period of time, and not as a result of the compressor failure. 1.7.3 Second-Stage Air Cooler Cover The second-stage air cooler cover contains a drain valve, a fusible plug and the high-pressure relief valve. At the time of the failure, this cover fractured into many pieces that were projected outward at high velocity. An optical microscope examination revealed fracture surfaces consistent with a brittle mode of failure such as would be present in an instantaneous overstress. No evidence of pre-cracking was observed. 1.7.4 First- and Second-Stage Air Cooler Tubes While none of the first-stage cooler tubes had failed, 18 of the 33 tubes that make up the second-stage tube nest failed in a manner consistent with an over-pressurization. Microscopic examination revealed no evidence of pre-cracking on the fracture surfaces of the tubes. Also, there was no indication of overheating or any evidence of combustion as would be expected subsequent to an explosion-type occurrence. The evidence therefore points to a bursting-type occurrence. Close examination and testing of both first-stage and second-stage air cooler tubes indicate that the first-stage tubes met manufacturer's specifications but the second-stage tubes did not. Specifically, the manufacturer specifies copper tube BS2871 which contains a minimum of 99.85 per cent copper and a wall thickness of 0.91 mm for both first- and second-stage tubes. The composition of the second-stage tubes installed on the compressor was found to be consistent with a UNS C68700 aluminum brass alloy, with wall thicknesses on average only half that of manufacturer's specifications. Furthermore, a close examination of these tubes revealed corrosion pitting that can be attributable to the absence of anti-oxidant additives in the cooling water. 1.8 The Compressor The No. 3 compressor was a Hamworthy type 2TM63 made in 1976 with a rated capacity of 350 cubic metres/hour at a pressure of 29.3 bar. This compressor was of the non-oil-free, reciprocating, two-stage water-cooled type. As of the end of December 1998, ship records indicate that the total number of running hours on the compressor was 48,002.